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Sheridan likens Ecuadoran volcano to Mt. Vesuvius
By ELLEN GOLDBAUM
Contributing Editor
Ecuador's El Reventador volcano awoke from a 35-year slumber on Nov. 3 with an eruption that makes other volcanic eruptions of recent years look "pale" in comparison, according to a UB geologist.
El Reventador, known locally as "the exploding one" and "the destroyer," is located in a remote section of the Amazon rainforest, but the power of its explosion sent tons of ash as far as Ecuador's capital, Quito, about 60 miles away, causing the city and its airport to close and causing the evacuation of about 1,500 villagers who live close to the volcano.
This view of Ecuador's El Reventador volcano was taken by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, within hours after the volcano erupted unexpectedly on Nov. 3, sending a cloud of ash 10 miles into the sky. In this scene, the volcanic plume appears grey and can be distinguished easily from the whiter clouds.
PHOTO: SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE
Michael F. Sheridan, professor of geology, noted that "while typical ash flows from volcanoes will travel just a few miles at most, this one traveled more than six miles."
Sheridan, who last month flew over Ecuador's erupting Tungurahua volcano as part of a research project, planned to conduct fieldwork at El Reventador this coming week, but canceled his plans based on a government ban on travel to the volcano. He said scientists in Ecuador estimate there is a 50 percent chance the volcano will have another major eruption in the next few months.
Sheridan said that not much has been published on El Reventador, which has been silent for more than 20 years.
One of the most interesting aspects of this Nov. 3 eruption, Sheridan noted, is the fact that there were essentially no precursors.
"This was a pretty fast trigger," he said. "Generally before an eruption, there are months or at least days of earthquakes that signal an eruption is imminent.
"In this case, there were only six hours of earthquakes, so it's pretty similar to Mt. Vesuvius in A.D. 79 that destroyed Pompei, where there was an earthquake in the morning and by the afternoon everyone in the vicinity was dead."
Sheridan noted that if the villages had been located closer to El Reventador's crater, the Nov. 3 eruption certainly would have been lethal.
Sheridan has spent the past decade developing small-scale computer simulations of geologic activity, primarily in Latin America, and has long advocated that the risks posed to human life by volcanic flows could be greatly mitigated by creating large-scale simulations of these phenomena. He is a member of a multidisciplinary team at UB that is using supercomputers to simulate Mexican volcanoes, funded by a $1.9 million National Science Foundation grant.
He had obtained NSF funding for the expedition to El Reventador that now has been postponed.
The purpose of the trip was to determine the course of the ash and mud flows and their physical properties, and to gather samples for analysis that would allow the scientists to better predict the hazards related to future eruptions at this volcano and at others.
"When we study this type of volcano, we look for changes in topography," said Sheridan. "We have models of the topography of volcanoes and surrounding areas before eruptions, and by combining our fieldwork and modern satellite data, we create three-dimensional models of differences in the earth's surface since the eruption. This allows us to make more accurate hazard maps for future eruptions of this type."